<!DOCTYPE html>
<script src="include.js"></script>
<script>
    function offsetParentOfChildDocument() {
        const frameDocument = document.querySelector("iframe").contentDocument;
        const frameRoot = frameDocument.documentElement;
        document.documentElement.append(frameRoot);
        document.dispatchEvent(new CustomEvent("offsetParentCalled", { detail: { iframeOffsetParent: frameRoot.offsetParent }}));
    }

    asyncTest(done => {
        document.addEventListener("offsetParentCalled", event => {
            println(`iframe offsetParent value: ${event.detail.iframeOffsetParent}`);
            done();
        });
    });
</script>
<iframe srcdoc="
<script>
    window.parent.offsetParentOfChildDocument();
</script>
">
